Case management is needed because, in most jurisdictions, services are fragmented and inadequate to meet the needs of the substance-abusing population. This lack of coordinated services results from a variety of factors, including:

• Different funding streams. Substance abuse treatment is funded from a variety of sources - block grants, competitive grants, state and local funding, criminal justice funding, and others. The different requirements or goals of these sources can result in a piecemeal approach to programming
• A focus on program funding rather than system funding
• Funding focused on single modalities rather than a continuum of care
• Inadequate funding created by missing pieces in the continuum
• Waiting lists caused by inadequate funding
• Barriers between systems (e.g., mental health vs. substance abuse, criminal justice vs. mental health and substance abuse)
• Lack of incentives geared to client outcome; programs rewarded for process measures, not outcome measures
• Eligibility/admission criteria that exclude certain clients
• Lack of agreement on priority for admission/treatment
• Lack of incentives for programs to work together

Due to the fragmentation of services, the accompanying inefficiency, and a growing scarcity of resources, some form of case management is used with virtually every population that routinely seeks social services. The variability in social services system configurations has led to many different implementations of case management, resulting in conceptual disagreements about case management and difficulty in assessing its value. Inevitably, many of the same issues will arise in the substance abuse setting.

Case management is a set of social service functions that helps clients access the resources they need to recover from a substance abuse problem. The functions that comprise case management - assessment, planning, linkage, monitoring, and advocacy - must always be adapted to fit the particular needs of a treatment or agency setting. The resources an individual seeks may be external in nature (e.g., housing and education) or internal (e.g., identifying and developing skills).

Advocacy is one of case management's hallmarks. While a professional conducting therapy may speak out on behalf of a client, case management is dedicated to making services fit clients, rather than making clients fit services.